1. Field of the Invention
The present invention relates to a nitride semiconductor light-emitting element and a method of manufacturing the same, and particularly relates to a nitride semiconductor light-emitting element and a method of manufacturing the same, which can improve manufacturing yield and reliability.
2. Description of the Background Art
A nitride semiconductor, which is represented by a composition formula InaGabAlcN (where a+b+c=1, 0≦a<1, 0<b≦1, 0≦c<1), for example, has a large energy band gap and high thermal stability. As to the nitride semiconductor, a band gap width can even be controlled by adjustment of the composition thereof. Accordingly, the nitride semiconductor is expected to serve as a material applicable to a nitride semiconductor light-emitting element such as a light-emitting diode or a laser diode, as well as various semiconductor devices, a typical example of which is a high-temperature device.
As to a light-emitting diode utilizing a nitride semiconductor, in particular, one having a luminous intensity as high as a few candelas in a wavelength range from blue light to green light has already been developed and implemented. Furthermore, implementation of a laser diode utilizing a nitride semiconductor is becoming a focus of research and development, as a light source of a pickup for a high-capacity optical disk medium.
For example, Patent Document 1 (Japanese Patent Laying-Open No. 09-008403) discloses an example of a conventional nitride semiconductor light-emitting element having an upper and lower electrode structure. As shown in a schematic cross-sectional view in FIG. 21, the conventional nitride semiconductor light-emitting element is configured such that a first ohmic electrode layer 102 and a second ohmic electrode layer 101 are formed on a conductive substrate 100 made of a p-type GaAs and having a positive electrode layer 107 formed thereat, that a nitride semiconductor layer stacked structure 108 in which a p-type nitride semiconductor layer 103, a light-emitting layer 104, and an n-type nitride semiconductor layer 105 are stacked in this order is formed on second ohmic electrode layer 101, and that a negative electrode layer 106 is formed on n-type nitride semiconductor layer 105.
The conventional nitride semiconductor light-emitting element is formed by joining, through thermocompression bonding, first ohmic electrode layer 102 formed on conductive substrate 100 and second ohmic electrode layer 101 formed on nitride semiconductor layer stacked structure 108 stacked on a sapphire substrate (not shown), and subsequently removing the sapphire substrate.